Present computer input/output communication is achieved using parallel data transfer over multiwired twisted pair cables. This type of interconnect system requires large multi-pin connectors and bulky cables. Numerous difficulties have been experienced with such interconnect systems. For instance, such electrical systems are susceptible to electromagnetic and electrostatic fields and the data transmission is not secure against detection. Also, the failure of the electrical cables cause an arcing and present a fire hazard and the system must be electrically isolated with impedance matching. In aircraft, the electrical interconnect systems are very bulky and are susceptible to electromagnetic cross-talk and interference (EMI). One factor which causes such systems to be bulky is the parallel word structure of the airborne digital computer. This bulkiness can be reduced by serial type interfaced word structure for the data processing system which greatly reduces the number of wires required for the interconnect system. Fewer wires decreases the transmission medium weight. However, even the serial type word structure using an electrical interconnect system presents problems of security, interference from electromagnetic and electrostatic fields, arcing, etc. In a typical aircraft computer, the communication from the computer to the peripheral consists of thirty bit parallel input data or command words with a complement of four input/output control signals. The same communication is required from the peripheral to the computer. While such a computer system will hereinafter be referred to for explanation purposes, it is understood that the number of bits and control signals can vary with the construction of the computer and peripheral.
The employment of fiber optic interconnect systems has been suggested for various applications. An optical link for illuminated travelling message display sign system is disclosed in U.S. Pat. No. 3,838,412 to Clifford M. Jones and John D. Harnden, Jr., granted Sept. 24, 1974. This patent discloses a multiplex method in combination with an optical link for serialized data transmission. More particularly, Jones et al discloses an optical data link comprising an optical transmitter in the form of a light emitting diode (LED), an optical receiver in the form of an optical detector, and parallel-to-serial and serial-to-parallel conversion in the transmitter and receiver stations. A basic electro-optical transmission line is disclosed in the U.S. patent to John F. Clanton, U.S. Pat. No. 3,809,908, granted May 7, 1974. This patent relates to an electrical-optical transmission line having a light emitting diode on the transmitting end and a photo-sensitive device such as an infrared photo diode on the receiving end. U.S. Pat. No. 3,473,036 to Thomas J. Marcus discloses a code matrix reader comprising an array of photovoltaic cells which emit electrical signals when they are exposed to light energy. Other U.S. patents of interest consist of Ohnsorge U.S. Pat. No. 3,801,819, Sanders U.S. Pat. No. 3,705,986, Rose U.S. Pat. No. 3,657,543, Englehardt U.S. Pat. No. 3,222,535, Raub U.S. Pat. No. 3,218,462, Puntchechnikoff U.S. Pat. No. 2,629,802, and Hunsperger U.S. Pat. No. 3,952,265. None of the interconnect systems of the prior art disclose a self-powered capability starting with digital signal levels and producing from this signal level both positive and negative voltages with enough power to operate a plurality of integrated circuits plus drive a plurality of LEDs and photo diodes with associated amplifiers.